1 files changed, 97 insertions, 0 deletions
diff --git a/dev/kernel/HALKit/AMD64/HalTimer.cc b/dev/kernel/HALKit/AMD64/HalTimer.cc
new file mode 100644
index 00000000..13573880
--- /dev/null
+++ b/dev/kernel/HALKit/AMD64/HalTimer.cc
@@ -0,0 +1,97 @@
+/* -------------------------------------------
+
+  Copyright (C) 2024-2025, Amlal El Mahrouss, all rights reserved.
+
+  File: HalTimer.cc
+  Purpose: HAL timer
+
+  Revision History:
+
+  07/07/24: Added file (amlel)
+
+------------------------------------------- */
+
+#include <ArchKit/ArchKit.h>
+#include <KernelKit/Timer.h>
+#include <modules/ACPI/ACPIFactoryInterface.h>
+
+// timer slot 0
+
+#define kHPETSignature ("HPET")
+
+#define kHPETCounterRegValue (0x00)
+#define kHPETConfigRegValue (0x20)
+#define kHPETCompRegValue (0x24)
+#define kHPETInterruptRegValue (0x2C)
+
+///! BUGS: 0
+///! @file HalTimer.cc
+///! @brief Hardware Timer (HPET)
+
+namespace Kernel::Detail {
+struct HPET_BLOCK : public Kernel::SDT {
+  Kernel::UInt8  hardware_rev_id;
+  Kernel::UInt8  comparator_count : 5;
+  Kernel::UInt8  counter_size : 1;
+  Kernel::UInt8  reserved : 1;
+  Kernel::UInt8  legacy_replacement : 1;
+  Kernel::UInt16 pci_vendor_id;
+  ACPI_ADDRESS   address;
+  Kernel::UInt8  hpet_number;
+  Kernel::UInt16 minimum_tick;
+  Kernel::UInt8  page_protection;
+} PACKED;
+}  // namespace Kernel::Detail
+
+using namespace Kernel;
+
+HardwareTimer::HardwareTimer(UInt64 ms) : fWaitFor(ms) {
+  auto power = PowerFactoryInterface(kHandoverHeader->f_HardwareTables.f_VendorPtr);
+
+  auto hpet = (Detail::HPET_BLOCK*) power.Find(kHPETSignature).Leak().Leak();
+  MUST_PASS(hpet);
+
+  fDigitalTimer = (UInt8*) hpet->address.Address;
+
+  if (hpet->page_protection) {
+    HAL::mm_map_page((VoidPtr) fDigitalTimer, (VoidPtr) fDigitalTimer,
+                     HAL::kMMFlagsWr | HAL::kMMFlagsPCD | HAL::kMMFlagsPwt);
+  }
+
+  // if not enabled yet.
+  if (!(*((volatile UInt64*) ((UInt8*) fDigitalTimer + kHPETConfigRegValue)) & (1 << 0))) {
+    *((volatile UInt64*) ((UInt8*) fDigitalTimer + kHPETConfigRegValue)) =
+        *((volatile UInt64*) ((UInt8*) fDigitalTimer + kHPETConfigRegValue)) |
+        (1 << 0);  // enable timer
+    *((volatile UInt64*) ((UInt8*) fDigitalTimer + kHPETConfigRegValue)) =
+        *((volatile UInt64*) ((UInt8*) fDigitalTimer + kHPETConfigRegValue)) |
+        (1 << 3);  // one shot conf
+  }
+}
+
+HardwareTimer::~HardwareTimer() {
+  fDigitalTimer = nullptr;
+  fWaitFor      = 0;
+}
+
+/***********************************************************************************/
+/// @brief Wait for the timer to stop spinning.
+/***********************************************************************************/
+
+BOOL HardwareTimer::Wait() noexcept {
+  if (fWaitFor < 1) return NO;
+
+  UInt64 hpet_cap              = *((volatile UInt64*) (fDigitalTimer + kHPETCounterRegValue));
+  UInt64 femtoseconds_per_tick = (hpet_cap >> 32);
+
+  if (femtoseconds_per_tick == 0) return NO;
+
+  volatile UInt64* timer = (volatile UInt64*) (fDigitalTimer + kHPETCounterRegValue);
+
+  UInt64 now  = *timer;
+  UInt64 prev = now + (fWaitFor / femtoseconds_per_tick);
+
+  while (*timer < (prev)) asm volatile("pause");
+
+  return YES;
+}